The fried chicken giant is suing one of it’s suppliers, saying the cups used to hold popcorn chicken caught on fire while being reheated in the microwave oven.

Louisville-based KFC said in a federal lawsuit that Paris Packaging Inc. of Paris, Texas, changed the content of the ink used on the containers, using a new formula that includes carbon, which may catch fire if heated.

The restaurant chain said at least two people reported fires. KFC said company employees then tested the cups in a microwave oven and, after being heated for 13-19 seconds, the cups caught fire.

KFC spokesman Rick Maynard said no one was injured because of the fires.

‘‘Since the safety of our customers is our top priority, KFC took immediate action by removing the packaging based on two reported issues,’’ Maynard said.

KFC, a division of fast food giant Yum Brands, is seeking at least $757,000 to cover the cost of more than 11,000 recalled containers and other unspecified financial damages. The company, in the suit filed Monday, also wants U.S. District Judge John G. Heyburn of Louisville to issue an order that KFC cannot be held responsible for any damage caused by the cups that combusted.

A message left for Paris Packaging was not immediately returned Tuesday morning. An e-mail sent to Paris Packaging President Bill Carver was not immediately responded to Tuesday.

KFC claims Paris Packaging, which has been supplying boxes and cups to KFC since 2007, changed the composition of the ink used to print labels on cups and boxes in February without notifying the restaurant chain.

The issue arose when a customer complained to KFC on Feb. 4 that the cup containing popcorn chicken ‘‘spontaneously burst into flames’’ while being reheated at a customer’s home, KFC said.

KFC sent a notice to all restaurants and franchisees on Feb. 20, telling them to stop using the Paris Packaging containers until further notice.

According to a series of letters attached to the suit, KFC and Paris Packaging had multiple discussions about how to handle the remaining containers in KFC’s supply chain and whether and how KFC would be reimbursed for the containers it could not use.

‘‘Simply stated, the containers are not safe for use by Yum or its customers,’’ KFC Vice President and General Counsel Matthew Preston wrote to Paris Packaging on March 27.

In another letter to Carver, dated March 12, KFC offered Paris Packaging an opportunity to remain as a supplier to the restaurant chain, provided it took financial responsibility for the recalled cups and boxes and modified the way the packages were made.

‘‘You then stated that, under these conditions, Paris Packaging has no interest in continuing to supply this packaging to the KFC system,’’ Preston wrote.